1. Field of the Invention
The present invention relates to a lamp, and more particularly to a lamp for a light string, wherein the lamp maintains an electrical connection when a bulb is removed.
2. Description of Related Art
Light strings having multiple lamps electrically connected in series and are popular during festival seasons such as Christmas day, New Year . . . etc. because all the lamps emit lights with the same illumination. One major drawback of the light string is that when a bulb in one of the lamps in the light string is removed, the other lamps in the same light string will not emit light.
One solution to overcome the above drawback is provided by U.S. patent application with Pub. No. 2006/0274556 (Massabki et al. hereinafter). With reference to FIG. 5, Massabki et al. disclosed a lamp comprising a light assembly (60), a socket (70), two electrodes (80) and a torsional spring (90). The light assembly (60) comprises a body (61), a bulb (62) and two extension members (63). The body (61) has a bottom. The bulb (62) is mounted in the body (61) and has two filaments (621) protruding oppositely from the body (61). The extension members (63) are formed separately on the bottom of the body (61). The socket (70) is cylindrical, corresponds to and receives the light assembly (60) and has a fulcrum (71). The electrodes (80) are mounted in the socket (70). The torsional spring (90) is mounted in the socket (70), is formed by winding an iron stick around the fulcrum (71) and has two arms (91). The arms (91) are selectively and respectively connected to the electrodes (80).
When the light assembly (60) is inserted in the socket (70), the extension members (63) will respectively force the arms (91) of the torsional spring (90) to be deformed away from contacting the electrodes (80), and the filaments (621) of the bulb (62) are respectively connected to the electrodes (80). When the light assembly (60) is removed, the torsional spring (90) will recover and be connected to the electrodes (80). Therefore, light emitted from the light string is maintained even when one bulb (62) is removed because the torsional spring (90) provides a bypass loop for a current flowing in the light string.
However, the torsional spring (90) is thin so it is easily deformed to lose resilience or broken. If the torsional spring (90) is fatigued, the arms (91) may not reconnect to the electrodes (80) when the light assembly (60) is removed or may remain in connected to the electrodes (80) when the light assembly (60) is inserted in the socket (70). If the connection ends (91) do not reconnect to the electrodes (80) when the light assembly (60) is removed, the light string with the conventional lamps will not emit light when the light assembly (60) in one of the lamps is removed. If the arms (91) remain connected to the electrodes (80) when the light assembly (60) is inserted in the socket (70), the bypass loop will be maintained and the light assembly (60) will not light and causing a short circuit. The torsional spring (90) will be heated up because the short circuit and may cause the lamp to burn out, or explode causing a fire hazard.
To overcome the shortcomings, the present invention provides a lamp with leaf spring to mitigate or obviate the aforementioned problems.